feat(enakgame): spin as an EnakGame game; remove the old game flow

EnakGame phase 10 of docs/tasks-enakgame.md (EG-1001 to EG-1003).

Spin (EG-1001)
- PROBABILITY entries take an optional label (a wheel segment). The customer game
  list shows a PROBABILITY game's prizes (entry, label, amount, never weights), and
  completing returns the drawn prize, so the client can draw the wheel and stop it
  on the server's draw.
- docs/enakgame-spin.md: the admin steps to set up spin per organization (no
  seeder) and the customer app flow. An HTTP test plays it end to end.

Old game flow removed (EG-1002)
- Routes POST /customer/spin, GET /customer/games, GET /customer/ferris-wheel, and
  admin /marketing/games, /marketing/game-prizes, /marketing/rewards, with their
  handlers, services, processors, repositories, validators, models, contracts,
  mappers and tests (GamePlayProcessor, SpinGameService, rewards, ...). This also
  closes RFC §15 findings 1 and 2 (double charge, spinning another org's game).
- Tables games, game_prizes, game_plays and rewards stay for ledger history.
  entities.StringSlice moves to its own file; the omset tracker (unrouted) keeps
  game_id but no longer embeds the old game response.

games.is_active dropped (EG-1003)
- Migration 000115; nothing reads metadata.coin_cost any more.

The EnakPoint integration docs now point at /customer/enakgame. The Postgres tests
were not run: no test database here. Migration 000115 has not been run anywhere.
The customer app must stop calling the removed endpoints before this is deployed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/models/enakgame.go

@@ -150,6 +150,18 @@ type CustomerEnakGame struct {
 	SessionTTLSeconds int       `json:"session_ttl_seconds"`
 	// The events making the game pay more right now, highest priority first.
 	Events []CustomerGameEvent `json:"events"`
+	// What a PROBABILITY game, such as a spin wheel, can pay, in the order of its
+	// configuration. Left out for the other reward types.
+	Prizes []GamePrize `json:"prizes,omitempty"`
+}
+
+// GamePrize is one entry of a PROBABILITY game, such as a segment of a spin wheel, as
+// the customer sees it: never its odds.
+type GamePrize struct {
+	// 1 for the first entry of the configuration.
+	Entry  int     `json:"entry"`
+	Label  *string `json:"label"`
+	Amount int64   `json:"amount"`
 }
 
 // GameSessionStart is the response of starting a game (§7.1).
@@ -199,6 +211,9 @@ type GameSessionCompletion struct {
 	// The daily limits that made the reward smaller than earned: USER_DAILY,
 	// GAME_DAILY or GLOBAL_DAILY.
 	LimitedBy []string `json:"limited_by,omitempty"`
+	// The entry a PROBABILITY game drew, for a spin wheel to stop on. Its amount is
+	// the base reward, before events and limits.
+	Prize *GamePrize `json:"prize,omitempty"`
 }
 
 type GameSessionRewardParts struct {